Thermal behaviour analysis of an MCM-D technology

The Centro Nacional de Microelectronica (CNM) exploits an MCM-D technology that uses a silicon substrate on which flip chips are mounted using a low cost screen printing technique. The substrates can be either passive with interconnection lines, R's, C's and L's or actives with a CMOS2.5 μm technology cells. The metals used in this technology are aluminium for interconnection purposes, tantalum silicide for making resistors and a multi-layer of wettable metalfor solder connection. In this paper we present a study of the thermal behaviour of this packaging technology. Measurements of sheet resistance and contact resistance versus temperature in the range of-28 to 100°C of the metals used in CNM'sMCM-D technology are shown. A set of classic test structures such as Kelvin contacts, CBR's and Van der Pauw structures have been used for this purpose as well as a Kelvin-like structure to test the contact resistance of the Flip Chip connection. This structure has been proven to be very sensitive allowing the measurement of changes in ball resistance in the range of mΩ.